The various Inmarsat FleetBroadband plans all do voice via VoIP. You can have a dedicated 64kb/s channel for voice, but you need the largest terminal (FB500) to be able to use it. VoIP works fine - there is latency, but since it's datagram service
via UDP, there's no need for fancy TCP spoofing like with e-mail and file transfers. If you're getting severe echo on a voice call because of latency, the cause is crappy VoIP software
on your PC/notebook/notepad, not the service
The top speeds you get are dictated by the terminal size. The FB150 (10" across) tops out at 150kbps, the FB250 (13") at 284kbps, and the FB500 (>24") gets up to 432kbps.
It's not the type of service you'd normally run a business on, but if you use the right setup and software
, it can be done. "Chatty" applications which handshake with the other end constantly will eat up bandwidth like you wouldn't believe. Webmail and other client-server apps are bad. Streaming video is worse. A smart e-mail client like Airmail is great because it's optimized for low bandwidth.
As twistedtree pointed out, HTTPS can be problematic because the encryption process (SSL - Secure Socket Layer, or TLS - Transport Layer Security) hides the data stream from the software process which "speeds" things up by spoofing TCP packet acknowledgments - the real speed killer in high-latency systems like geosynchronous satcoms). That's a whole other technical discussion beyond the scope
of this thread, but if you need speed and security
, there are devices called PEPs (performance enhancing proxies) which can speed things up dramatically. They are expensive, but if you're running a business then it's just a tax-deductible expense...